BOSTON – Gastric bypass surgery appears to be linked to increased long-term fracture risk, based on a retrospective study of 258 bariatric surgery patients.
"Bariatric surgery results in an increased risk of fractures. We think the important take-home point here is that we need to start looking at the skeleton as one of those key areas for long-term follow-up," Dr. Kurt Kennel said at the annual meeting of the Endocrine Society.
The fracture risk for bariatric surgery patients in this study was 2.3 times greater than that for individuals who did not have bariatric surgery, reported Dr. Kennel of the endocrinology department at the Mayo Clinic in Rochester, Minn.
The findings are particularly important given the increasing number of severely obese individuals who are turning to bariatric surgery as a treatment option.
"We have questions about what this means in the long term," said Dr. Kennel. In this study, the mean time to first fracture was 6 years, with a mean follow-up of 9 years. However, in much of the current literature on bariatric surgery, patients are followed only 1-2 years and the only issues addressed are related to surgery or weight.
"Some issues – like bone, for example – may not show the manifestations of these effects for many years, and therefore we may be missing some of those effects," said Dr. Kennel.
The researchers used data from the Rochester Epidemiology Project to conduct a retrospective study of fracture incidence. The REP Project connects medical records from the Mayo Clinic, local hospitals, and local private practices.
The study included data from 258 patients, who underwent a first bariatric surgery between 1985 and 2004 at the Mayo Clinic. Fractures were expressed in standardized incidence ratios that compare the number of observed fractures to the number of expected fractures by skeletal site.
Expected fracture data were derived by applying age- and sex-specific incidence rates from the local population to the age- and sex-specific person-years of follow-up.
The average age of the bariatric surgery patients was 44 years and most (83%) were female. Following bariatric surgery, 79 patients experienced 132 fractures. Bariatric surgery patients had an increased risk of fracture at nearly all of the skeletal sites studied, not just in weight-bearing bones.
Also of note, 94% of these patients had undergone gastric bypass procedures. Dr. Kennel attributed this to the time frame used in the study. Other bariatric surgical procedures – such as adjustable gastric banding and sleeve gastrectomy – are more recent developments. Dr. Kennel acknowledged that different bariatric procedures might yield different fracture risks. For now though, it’s unclear what is driving the fracture increase in these patients.
The increased rate of fractures following bariatric surgery "suggests that structural and biochemical changes in bone that are observed after bariatric surgery are clinically important. Clinicians should discuss bone health with patients who have undergone or are considering bariatric surgery."
Dr. Kennel reported that he and his coinvestigators have no significant financial relationships to report.